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April 28, 2008
Constraint Competitiveness Tests, an Overview
Congestion Management Working Group
April 28, 2008
• Overview of the Competitiveness Constraints Test (CCT)
• Key Implementation Notes
• Data Structure for Inputs
April 28, 2008
Two test procedures are employed in the CCT:
• In Test Procedure 1 the effective capacity available to resolve the constraint on both the import and export side is first determined. The available effective capacity is then used to compute the Element Competitiveness Index (ECI), an index similar to the Herfindahl-Hirschman Index (HHI) on the import and export side.
1. Determine effective capacity available to resolve the constraint on the import side
2. Determine effective capacity available to resolve the constraint on the export port side
3. Determine Element Competitive Index (ECI)
• In Test Procedure 2, analysis is conducted to check for the existence of any pivotal player.
Overview of the Competitiveness Constraints Test (CCT)
April 28, 2008
E iLimit
Effective load(max withdraw)
Eff. Cap.>(Load +Limit)
Generation
Entity a b c n . . . . .
Test 1-AImport ECI
April 28, 2008
E iLimit
Effective load Eff. Cap. >(Load -Limit)
Generation
Entity a b c n . . . . .
Test 1-BExport ECI
Test 2 – Pivotal Player
1. Remove Largest Entity2. Balance System Power3. If load can be served (PP does not exist)
April 28, 2008
HHI: Measuring Market Concentration
• Market Concentration is a function of the number of firms in a market and their respective market shares
• Herfindahl-Hirschman Index ("HHI") is a widely used measure of market concentration – also used by the Dept. of Justice (DOJ)
• The HHI is calculated by summing the squares of the individual market shares (in percentage) of all the participants
• HHI gives proportionately greater weight to the market shares of the larger firms, in accord with their relative importance in competitive interactions
• DOJ divides spectrum of market concentration as follows: – Unconcentrated (HHI below 1000)– Moderately concentrated (HHI between 1000 and 1800), and– Highly concentrated (HHI above 1800)
Note: Taken from Shams Siddiqi presentation 10/16/2006
April 28, 2008
HHI: Examples
• Ex 1: Market consisting of 5 equally sized entities each controlling 10,000 MW– Each entity controls 20% of supply– HHI = 5 x (20)^2 = 2,000
• Ex 2: Market consisting of one 20,000 MW entity and four 7,500 MW entities– Big entity controls 40%, others 15% each– HHI = (40)^2 + 4 x (15)^2 = 2,500
• For electricity markets, some consider HHI of 2,000 as “workably competitive”
Note: Taken from Shams Siddiqi presentation 10/16/2006
April 28, 2008
Test Procedure 1, Constraint fails the competitive test if the ECI is:
Import Side Export Side
Annual >2000 >2500
Monthly >2500 >3000
Daily >2500 >3000
Overview of the Competitiveness Constraints Test (CCT)
April 28, 2008
CCT test is to be performed• Annually• Monthly• Daily
Annual Competitiveness Test shall determine if a constraint is competitive or not for each month of the year (This information may be used to make recommendations on the status of constraints for the Annual CRR Auction as well as inputs to the Monthly CCT)
Monthly Competitiveness Test shall change the treatment of a Competitive Constraint to a non-competitive constraint for a particular month
Based on the set of the Competitive Constraints as determined in the Monthly Competitive Test, the Daily Test shall change the treatment of a Competitive Constraint to a non-competitive constraint for a particular day
April 28, 2008
6.5.7.3. (5)The two-step SCED methodology referenced in paragraph (1) above is:
(a) The first step is to execute the SCED process to determine Reference LMPs. In this step ERCOT executes SCED using the full Network Operations Model while only observing limits of Competitive Constraints. Energy Offer Curves for all On-Line Generation Resources, whether submitted by QSEs or created by ERCOT under this section are used in the SCED to determine “Reference LMPs.”
(b) The second step is to execute the SCED process to produce Base Points, Shadow Prices, and LMPs, subject to security constraints (including Competitive and Non-Competitive Constraints) and other Resource constraints. The second step must:
(i) Use Energy Offer Curves for all On-Line Generation Resources, whether submitted by QSEs or created by ERCOT. Each Energy Offer Curve must be capped at the greater of the Reference LMP (from Step 1) at the Resource Node or the appropriate Mitigated Offer Cap and bounded at the lesser of the Reference LMP (from Step 1) at the Resource Node or the appropriate Mitigated Offer Floor; and
(ii) Observe all Competitive and Non-Competitive Constraints.
April 28, 2008
Contingency/limiting Transmission Element pairs
3.19 (1) Unless the Board approves changes, the “Competitive Constraints” are the contingency/limiting Transmission Element pairs that represent the Commercially Significant Constraints (CSCs) and Closely Related Elements (CREs), as those terms were defined in the ERCOT Protocols, immediately prior to Texas Nodal Market Implementation Date.
April 28, 2008
This phrase was added to CCT requirements document and approved by TPTF.
2. Constraint Competitiveness Test (CCT)TAC shall consider on an annual basis the results of the Constraint Competitiveness Tests (CCT) performed on each candidate constraint to determine if the constraint is “Competitive” or ”Non-Competitive”. For the first year of the Nodal Market, these constraints are the contingency/limiting Transmission Element pairs that represent the Commercially Significant Constraints (CSCs) and Closely Related Elements (CREs) and will be defined immediately prior to the Texas Nodal Market Implementation date.
Overview of the Competitiveness Constraints Test (CCT)
April 28, 2008
If the CSCs are used as the initial constraints
1. ERCOT proposes that the CSC’s be disaggregated into individual line segments (constraints) for the CSC
2. The CSC limits will also need to be allocated to each constraint 3. Use contingencies out of TCM
April 28, 2008
Constraints to be Tested in CCT
• Protocol: each transmission constraint • Each constraint is a contingency/limiting transmission element
pair• Contingency = Closely Related Element (CRE)• Limiting Transmission Element = Commercially Significant
Constraint (CSC)
April 28, 2008
• Number of Transmission Lines: 5000• Number of Contingencies: 2500• Brute Force Setup
– Number of transmission constraints to be tested = 5000 * (2500+1) = 12,505,000
Note: “1” represents base case • Impractical due to the large number of transmission
constraints to be tested
April 28, 2008
Practical Data Setup
• Contingencies must be closely related to monitored element• A contingency, which is far away from a transmission line, will
not cause violation on that transmission line.• Consequently, every transmission line does not have to be
tested against all contingencies
April 28, 2008
Example
Contingency Outage Element
1 A-B ckt 1
2 A-B ckt 2
3 C-A
4 D-E
5 F-G
A BC
ckt 1
ckt 2
D
E
F
G
April 28, 2008
CCT Constraint Data Setup
Contingencies Monitored Element
(constraint)
Base Case A-B ckt 2
Contingency 1 A-B ckt 2
Contingency 3 A-B ckt 2
To test A-B ckt 2
April 28, 2008
Input Files for Annual CCTCCT001.PSE ~ CCT012.PSE (PSS/E Version 30)CCT001.CTG ~ CCT012.CTGCCT001.CNT ~ CCT012.CNTCCT001.RMP ~ CCT012.RMP
Input Files for Monthly CCT
CCT001.PSE (PSS/E Version)CCT001.CTGCCT001.CNTCCT001.RMP
PSE – Planning model for monthly peak case used to auction on-peak CRRsCTG – Contingency listCNT – Constraint listRMP – Resource mapping to Decision Making Entity
April 28, 2008
Format Definition of CCT00X.CTG1 'SL_35_34_1 ' 1'BRA' 1 0 ' ' 36 35 '1 ' 0 0 0.00-999-999-999-999-999
First Line: FORMAT (I5, 1X, A32, 1X, I2)1. Contingency Sequence #2. Contingency Name3. No Use
Second Line: FORMAT (A5,1X,I2,1X, I5,1X,A3,1X, I5,1X,I5,1X,A4,1X,I5,1X,I5,1X,F8.2)
1. Contingency Type: “BRA”, “GEN”, “LOA”2. Contingency Operating Type: 1 = Outage3. Generator or Load Bus # (PSS/E column 1 of
Generator or Load Section)4. Generator or Load ID (PSSE/E column 2 of
Generator or Load Section)5. From Bus # (Branch Only)6. To Bus # (Branch Only)7. Circuit ID8. No use9. No use 10.No use
Third Line: FORMAT (I5)1. End of Individual data (or separator)
Fourth Line: FORMAT (I5)1. End of Contingency section
Fifth Line: FORMAT (I5)1. End of Flow Gate section
Sixth Line: FORMAT (I5)1. End of Generic Constraint section
Seventh Line: FORMAT (I5)1. End of SPS section
1.2.3.4.5.6.7.
April 28, 2008
Format Definition of CCT00X.CNT
0 'BASE CASE : STATION A - STATION B ' 10.0 1 2 1 0 18 'SL_1063_175_1 : CRLNW__PTENN__LN01 ' 1185.0 1072 183 0-9999 First Line: FORMAT ( 1X, I5, 1X, A67, 1X, F7.1 )1. Contingency Sequence # in NDPXXX.CTG ( BASE CASE = 0 )2. Contingency Name (A32) and Constraint ID (A32)
Note: A67 = A32 “Contingency Name” + A3 “ : “ + A32 “Constraint ID”3. Constraint Limit
Second Line: FORMAT ( 1X, I5, 1X, I5, 1X, A2 )1. From (Export) Bus #2. To (Import) Bus #3. Circuit ID
Third Line: FORMAT (1X, I5)1. End of Individual data (or separator)
Fourth Line: FORMAT (1X, I5)1. End of Constraint Mapping File
1.2.3.1.2.3.4.
April 28, 2008
Format Definition of CCT00X.RMP
1 'N' ‘ABC ' 0.5000 ‘LMN ' 0.4000 ‘XYZ ' 0.1000 -9999 First Line: FORMAT (1X, I5, 4X, A1)1. Generator Sequence # in PSSE2. Generator Type: N = Nuclear, C = Coal, L = Lignite, Other = blank
Second Line: FORMAT (7X, A32, 1X, F7.4) – repeated for each decision making entities1. Entity Name2. portion of the entity
Third Line: blank line1. End of Individual data (or separator)
Fourth Line: FORMAT (1X, I5)1. End of Resource Mapping File
1.2.2.2.3.4.
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